海参卵纳豆菌发酵条件及产物生物活性

摘要

为开发新的功能性海参卵产品,以刺参加工副产物——海参卵为原料,作为纳豆菌发酵基质,以溶纤酶活力作为评价标准,考察不同发酵条件对发酵产物中溶纤酶活力的影响.结果显示,最适发酵碳源为葡萄糖,其最适质量分数为2％;其他最适条件分别为初始pH 7、接种量5％、发酵温度37℃、装载量20％、料液比1∶30 (g/mL)、摇床转速180 r/min.海参卵发酵产物经7 000 r/min离心20 min后,对上清液的部分生物活性进行了检测,结果显示上清液的溶纤酶活力较强,当总蛋白质量浓度为20 mg/mL时,上清液的溶纤酶活力为6 723 FU/mL,对血管紧张素转换酶抑制率约为90％.当总蛋白质量浓度为5～20 mg/mL时,上清液可明显延长活化部分凝血活酶时间和凝血酶时间,还可降低纤维蛋白原含量,而不影响凝血酶原时间.另外,明胶酶谱结果显示,发酵上清液中含有多种蛋白酶.因此,海参卵纳豆菌发酵产物具有较强的溶栓、降压及抗凝血活性,对心血管疾病具有潜在的辅助治疗作用,值得进一步深入开发.%This study aimed to develop a new functional product by fermenting sea cucumber ovum,a by-product of sea cucumber processing,with Bacillus natto.Fibrinolysin (FIB) activity was measured as an index to optimize the fermentation condition.Results showed that the optimum carbon source was glucose at a concentration of 2％.The optimized results of other fermentation parameters were as follows:initial pH,7;inoculum amount,5％;fermentation temperature,37 ℃;medium loading volume,20％;solid-to-liquid ratio,1:30 (g/mL);and rotational speed,180 r/min.The fermentation supernatant,collected after centrifugation at 7 000 r/min for 20 rain,demonstrated FIB activity as high as 6 723 FU/mL and ACE inhibition activity with a high inhibition percentage of 90％ at a final protein concentration of 20 mg/mL.The time required for partial activation of thromboplastin and the thrombin time were significantly extended by the supernatant when the protein level was 5-20 mg/mL,and it also decreased FIB content while having no influence on prothrombin time.Furthermore,some proteases in the supematant were observed by zymography.Therefore,the fermentation product of sea cucumber ovum showed relatively strong thrombolytic,antihypertensive and anticoagulation activities,demonstrating a potential auxiliary therapeutic agent for cardiovascular disease.Hence,it deserved further development.